For data communication between devices over a wireless local area network (LAN), some security standards have been recently developed by the Institute of Electrical and Electronic Engineers (IEEE), for example, and data communication can be performed relatively safely by following these standards.
For example, in a case of a wireless LAN, because devices communicate with each other in a relatively small area where the radio waves can be received, and a user of each of the devices can check the other devices belonging to other communicating users, available is a technology in which a shared private key is distributed to and used among the devices belonging to communicating users who can be identified by one another, to achieve highly confidential wireless communication. Examples of related art include those disclosed in Japanese Laid-open Patent Publication No. 2001-345795, Japanese Laid-open Patent Publication No. 2006-197063, Japanese Laid-open Patent Publication No. 2009-134731, Japanese Laid-open Patent Publication No. 2011-030608, and Japanese Laid-open Patent Publication No. 2003-030155.
In establishing connection between devices over a network, such a conventional technology can fail to establish connection to appropriate designation devices.
To establish a secure connection between all devices connected not only to a wireless LAN but also to a long-distance network such as the Internet, it is necessary to determine if a designation device is a legitimate designation. In making such a determination as to whether the designation device is a legitimate designation, information such as a unique number of the device, a media access control (MAC) address, an Internet Protocol (IP) address, a Wired Equivalent Privacy (WEP) key, or a serial number of the device is used. However, because these types of information are information that can be falsified by a third party, the conventional technology is incapable of validating the legitimacy of a designation appropriately.